Process of manufacturing vessels and the apparatus used



Jan. 23, 1934. E. PFAENDLER 1,944,527

PROCESS OF MANUFACTURING VESSELS AND THE APPARATUS USED Filed July 10. 1951 l v by the drawbacks connected with the old proc- Patented Jan. 23, .1934.

rnoonss or mums-mama vessels m rm: arraaa'rus usnn man Ptaendler, Olten, Switzerland Application July l0, 1931, Serial and in Germany July 15, 1930' 3 Claims. (Cl. 113-49) The present invention relates to a new and improved process and to improved means for pro. ducing hollow-ware from sheet-metal and more particularly to the manufacture of cooking vese sels from aluminium, pots, cans etc.

In the maniacture of such vessels it has been necessary up to now to stamp a sheet metal piece to the requisite shape and after being first cupped to draw it into shape by a series of stamping operations according to the depth oi. the vessel to be produced. The main object of the invention is to obviate the several steps and to bring the vessel into shape in but one operation whatever the size and height of the vessel may be and to obviate thereesses now in general use.

, Another object of the invention is to simplify the tools to draw such vessels and to reduce the time to produce said vessels. A further object of the invention consists in the provision of means to work the side walls of the vessel, in such a manner that the thickness disc for instance 01 aluminium held in a composite die in the usual manner is pressed by a former through a die and in immediate succession thereto through an annular die of steel, the former being provided with .an annular slanting recess or groove at a certain predetermined dis-v tance from the iace of the former. By these means the vessel is not only drawn into cylindrical shape, but while it is being drawn metal is squeezed by said annular die and a thickening of. the wall of the vessel at its upper edge is simultaneously produced. By the use of the annular steel die in conjunction with the ordinary drawing dies the side wall .oftheyessel is worked inside and outside, the walls areburnished or polished simultaneously wth theshaplng thereof. Moreover. the sheet metal is highly compressed and the walls are perfectly smooth. no further polishing being necessary. To produce vessels of a given heightsheet-metal discs of the wall is less near the bottom than at its of less diameter may be used in'the known processes and vessels or any height mightbe pro duced in but one drawing operation.

In the drawing the new device is shown in a diagrammatical manner.

Fig. 1 shows the die in a cross-section. Fig. 2' illustrates a vessel in section produced by the die shown in Fig. 1.

In the drawing 1 denotes a circular disc of sheet metal say of aluminium, which is to be shaped to a vessel shownin l 'ig. 2.- The disc 1 is held at its-circumference by a ring 4 which is pressed against the flanged portion 3 of the die A. The die A is arranged within a flange 11,012 a bottom plate 12 and rests on an annular die 5 of steel. The die 5 is concentrically arranged with, reference to the die A and to the bore 13 of plate 12. In the plate 12 a number oi strippers 6 are arranged which rest on coiled springs 14 arranged in radial bores of said plate 12. The

ends or said strippers project in the bore 13. theirv faces are bevelled in such a, manner that they are being pressed into the said bores whenthe vessel is ejected from the die. The annular die 5 is provided with an inwardly projecting g0 ridge 15., With the dies 5, A, co-operatesthe plunger '7 which is by the press pushed through the dies the metal disc 1 being withdrawn from between the parts '3. 4 and being cupped and shaped in the well known manner. To reduce 5' the tension etc. in the disc the edges 9 and l0 of die and former respectively have to be roundedoil. The plunger '7 is provided with a recess or reduced portion 8, the wall oi." the recess being slanting.

- In operation the" plunger 7 by withdrawing the disc 1 from its holding device shapes the disc 1... to a flat bottomed cylindrical vessel. As soon as the so-shaped vessel leaves the die A it enters the annular die 5. The ridge 15 now works on the sidewall compresses the metal and moreover squeezes the metal upwards. The displaced metal is pressed into the recessed portion 801' the plunger '1. The vessel produced by the die is shown in section in Fig. 2. The side wall 16 is thickened at the upper edge at 19 the shape conforms to the reduced, portion 8 of the former. By choosing appropriate dimensions of the parts 5, 15, '1 ends the thickness or the side wall 16 near the bottom 1'1 0! the vessel 2 is less than that otthe bottom 17, or of the disc 1 in the region nearest the'bot tom while the thickness oi the upper edge 19 is equal to afideven greater than that or bottom 17. By. withdrawing the edge of the vessel and strip the latter from the plunger 7.

By the device 'describedvessels can be easily produced in but one drawing operation the height of which is equal to or in excess of the diameter of the vessel. The'side walls of the vessel 2, the

inner and the outer are perfectly smooth, the

walls are free (if flaws and non-porous and no subsequent polishing operation is necessary. .The density of the material is materially increased and by using aluminium its tenacity is for instance increased from 21.5 kg/cm to 43 kg/cm.

I am aware that certain details may be varied through a wide range without departing from the principle 01- this invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art.

What I wish to secure by U. S. Letters Patent, 1s:-

1. The method of drawing metal and forming hollow ware therefrom, consisting inforcing "a blank through a die having an inwardlyextending ridge spaced from its lower side by means of aplunger having an upwardly taperingupper portion, spaced from its lower end, so that the portion of the blank forming the wall of the hollow ware article is progressively thickened and the diameter of the space within the wall pro gressively decreased upwardly as the upwardly tapered portion of the ridge of the die.

2. Apparatus for drawing metal and forming hollow ware therefrom, comprising a die having an inwardly extending ridge spaced from its lower plunger passes the side, and also spaced from its upper side and the upper portion of the face of which is curved and gradually diametrically contracts downwardly and the lower portion 01' which gradually diametrically expands downwardly, and a plunger arranged to force and draw a blank downwardly through the die, said plunger having an upwardly tapered portion so spaced from its lower end as to pass below the ridge of the die when a drawing stroke is imparted to said plunger.

EMIL PFAENDLER. 

